Telephone system



A118- 31, 1937. si B. wrLLlAMs TELEPHQHE SYSTEM Filei April 18. 1935 :ssheets-sheet 1 ATTORNEY ng- 31, 1937. s. B. WILLIAMS 2,091,541

' TELEPHONE SYSTEM Filed April 18, 1935 :5 `swans-sheen; 2

/Nl/E/vro/P 5. B. W/LL/AMS A TTORNEV Aug. 31, 1937. s. B. WILLIAMS2,091,541'

TELEPHONE SYSTEM Filed Apr'ii 1e, 1935 s sheets-*sugers FIG. 5-

, /N VE /V TOR s. W/L L MM5 A TTORNEV Patented Aug. 31, 1937 UNETE BellTelephone Laboratories,

Incorporated,

New York, N. Y., a corporation of New York Application April 18, 1935,Serial No. 16,947 13 Claims. (Cl. Ilill-6.31)

This invention relates to telephone systems and particularly to thosehaving coin-controlled stations.

The objects of the invention are to extend the range of serviceavailable to patrons of coin sta.-

tions; to enable them to call different classes of lines withoutassistance of an operator; to enable them to refund coins deposited forthe purpose of making free calls; and to otherwise improve systems ofthis character.

It has been the practice heretofore to equip coin-controlled stationswith dials to enable the patron to complete certain calls without the yassistance of an operator. In some of these prior 10 systems, if hewishes to make a long distance call or a call to a free line, he mustdeposit a coin to obtain the service of the operator, and

in other systems he may, without depositing a coin, obtain herassistance by dialing a particular number.

A feature of the present invention is to improve these priorarrangements by means of a system in which the coin station is equippedwith a device so that the patron may refund his e5 deposited coin at anytime, and which system is so arranged that he mai7 refund his coinwithout releasing the connection if he has called a free line, but, ifhe attempts to recover the coin on a call to a line for which a coinshould be collected, the connection is automatically released. To thisend the free lines are segregated in special final switches which areprovided with timing devices to delay the release for an intervalsucient to allow the refund of the coin at the calling station and thereclosure of theline to hold the connection.

A further feature is a refund key at the coin station so constructedthat it not only refunds the coin when actuated but opens the line andthen recloses it after a measured interval of time.

These and other features of the invention will be described more fullyin detail in the following specification which should be taken inconnection with the` accompanying drawings.

Referring to the drawings:

Fig. l shows in a diagrammatic form a coin station A and a line l, alineefinder LF having access to the line l, a first selector switch SI,

and a second selector switch S2.

Fig. 2 shows in diagrammatic form an alternative coin station B and aline l50 to which the line-lnder LF may have access.

Fig. 3 shows a connecter switch CI wired in accordance with thisinvention and, having access to any called subscriber station such as X,a connecter switch C2 of a type well known to the art and having accessto any called substation such as Y, and a circuit to an interceptingoperators position 0 also wired in a manner well kno-wn to the art andwhich gives an indication to an intercepting operator who may complete'the call.

Figs. 4 and 5 show details of the coin return mechanism of Figs. 1 and 2in the different operated positions. The numerical designationscorrespond with those shown in Fig. 1.

Fig. 6 shows in diagrammatic form the special dial used in Fig. l. Thenumerical designations of the springs correspond to those of the dialshown in Fig. 1.

It is to be understood that the invention is not limited to the use ofthe particular apparatus shown in the drawings, as the apparatus and thecircuits may be changed or modified in order to perform the desiredcircuit functions. Only such parts of the circuits as are necessary toillustrate the invention have been shown.

Substation A, in addition to the usual receiver and transmitter,comprises a special coin collect mechanism consisting of contact springs3S, a coin chute 3l, a coin trigger 32, a coin trigger lever 29, a cointrap 33, a non-polarized coin magnet M, and a copper oxide rectifier i5.Substation A has also a special governor and coin return mechanism Glwhereby the calling subscriber may return his coin when making a freecall. This coin return mechanism Gl consists of a coin return button Gliattached to coin return lever 38. One end of coin return lever 38 towhich is attached return button lill protrudes from the frame 56 of thecoin box and the other end rests on roller i3 and has lever arm Elsuitably attached. Associated with lever arm 4l! is a T-arm 35 pivotedat 3&3. The `i`arm 35 has a spring 3l suitably attached at one end t l.The other end of the spring 3l is attached to a pin SB on the frame ofthe coin box. In the normal position T-arm 35 rests against the stop 62,and the control springs lil are closed as shown in Fig. l. Associatedwith the coin return lever 38 is a gear wheel d5 which is attached tothe end 46 of a shaft 4l. Adjacent to the gear Wheel l5 is a spiralspring 5i) one end of which is attached to the frame of the coin bio-Xand the other end of which is attached to a link 138 which in turn, issuitably attached to shaft lil. At the other end of shaft 4l is attacheda lever arm 54 associated with a ratchet 5i. Ratchet 5l is actuated by ahelical spring 53. Associated with ratchet 5| is a ratchet wheel 52which in turn is connected to governor 56 by means of shaft 55.

In addition to this apparatus, substation A has a special dial in orderto prevent the calling sub- 5 station A from dialing any digit otherthan 0 without depositing a coin in the coin mechanism. This dial isshown diagrammatically in Fig. 6, and its outward appearance is similarto that of any standard dial. It has a finger wheel E34, l a numberplate H85 and a nger stop lSB. The interior of the dial has a specialconstruction and consists of contact springs 2 to 9 inclusive, a cam ES@which rotates in unison with the finger wheel E813, a lever arm ISIwhich has 4a roller i8@ l5 conveniently attached at one end and whichjoins spring li so that any movement of lever arm i9! is transmitted tospring 4, a collar l8l having .an inner surface E82 and an outer surfaceit, a pulse pawl I8?, a pulse pawl spring E92 and a pulse wheel H39.When the iinger wheel it is moved from its normal position the cam i9@moves in a clockwise direction and permits springs 5 and 'i to makecontact and springs 65 and 5 to break contact. As soon as the iingerwheel i 84 is moved in a clockwise direction, roller I8@ on lever armi9! will contact with the surface l82 of collar lili and move lever armi9! in such a manner as to keep springs 2 and l from breaking contactand springs 2 and 3 from making contact until the digit 0 has beencompletely dialed, when the roller I8@ will drop from surface 32 ofcollar ll and permit spring 2 to make contact with spring 3 and spring 4to break contact with spring 2. When the finger wheelV it@ is releasedthe roller H80 on lever arm i9! will contact with surface |83 of collarl 8i in such a inanner as to hold springs 2 and i open and springs 2 andS closed until the finger wheel l has restored to its normal positionwhere the lever arm lill again assumes its normal position as shown inFig. 6. The pulsing springs 8 and 9 are operated in the usual manner bypulse pawl itl which is pivoted at 88 and actuated under control of thepulse wheel l89 and the pulse pawl spring 92.

The finder LF, the selectors Si and S2, and the connecters CI and C2 arein general of the well-known type, such as the Strowger switch, exceptfor circuit modications made in connecter Cl in accordance with thisinvention. Other types of switches may be used if desirable.

Referring to Fig. l, let us assume that a party at the callingsubstation A removes the receiver 23 from the switchhook i9 to make acall to the subscriber of line X. In this case payment is not required,although a coin must be deposited temporarily to enable him to make thecall. When the receiver 23 is removed from the switchhook i9 a metallicloop circuit will be closed through substation A from terminal llt, overline l, conductor lil, the back contacts of con tact springs 35B,springs 3 and A of the dial,rconductor 25, transmitter i6, conductor i8,the left contacts of switchhook i9, the left winding of induction coil29, conductor 2l, line l to terminal ll. A receiving circuit will beclosed from conductor iii, through condenser 22, the right winding ofinduction coil 2i), the right contacts of switchhook l, receiver 23,conductor 2li, contact springs 5 and B of the dial to conductor it.

The brushes i3 and 'M of the line finder LF' will connect with theterminals Till 4and lil, in a manner well known to the art, and extendthe metallic loop circuit of substation A described above through to aselector Switch Si. The selector switch SI will function to send dialtone to the calling substation A and to place negative battery onconductor 2| and ground on conductor l il of the metallic loop circuitof substation A.

Under these circumstances dial tone will be heard in the receiver 23 ofsubstation A. If no coin has been deposited at the calling substation A,the contact springs 30 of the coin mechanism of substation A will notoperate and since contact springs 2 and 3 of the dial Will not makecontact when any digit other than 0 is dialed the pulsing circuit willno-t be closed through. This prevents dialing from the callingsubstation A until va coin is deposited in coin chute 3l of the coinmechanism.

If on or before receiving the dial tone, the calling party deposits acoin 28 in the coin chute 3i, the coin 28 will pass through the o-oinchute 3l to the coin trap 33 thereby operating the coin trigger 32 whichin turn will allow the coin trigger lever 29 to operate. Operation ofthe coin trigger lever 29 will cause the contact Springs Eil to functionclosing the front contacts and opening the back contacts of said Contactsprings Opening of the back contacts will open the transmitter circuit.Closure of the front contacts of springs 3i! will close a loop circuitthrough conductor il, the pulsing springs t and 9 of the dial, conductorlli, thence in parallel, one path leading to copper oxide rectifier l5,winding of coin magnet lll, conductor l2 to conductor i8, and the otherpath leading from conductor i3, rectier il, transmitter it to conductori8. The copper oxide rectiers i5 and ll are unipolarity devices whichwill not permit current toy pass through in the direction opposite tothat indicated by the symbolic arrowhead. Therefore, coin magnet lliwill not operate. However, current does flow over the loop and throughthe path including rectier il'. This holds the switches while the dialis in its normal position. When the dial is moved from normal to send adigit, it completes the pulsing circuit through from conductor l@ toconductor il, pulsing springs 8 and 9 of the dial, 01T normal springs tand l of the dial, conductor it, the left contacts of switchhook i9, theleft winding of induction coil 2l) to conductor 2l. Contact springs 2, 3and l of the dial will not operate when a digit other than 0 is dialed.As the dial is moved off-normal,

contact springs 5 and t of the dial break contact to open the receivercircuit and contact springs t and l make contact to place a shortcircuit around the coin magnet l@ `and at the same time to close thepulsing circuit to conductor i3. dial is then operated and released inthe usual manner causing the selector Sl and the selector S2 to functionin a manner well known to the art.

Assume that selector S2 seizes connecter CI thereby closing thesubscriber loop of substation A from brush i3 of line iinder LF toconductor it of. connecter Cl, the upper back contact of relay 395,conductor 396, the upper winding of relay Stil to ground, positivegrounded battery, the lower winding of relay 35i, conductor Sill, thelower outer back contact of relay 335, conductor lll to brush lll ofline finder LF. Closure of this loop circuit causes relay Sti to becomeenergized and close its front contact, thereby closing a circuit fromground through the front contact of relay 3M, winding of slow-to-releaserelay 3632 to battery. Relay 3632 becomes energized and closes a circuitfrom ground through the left outer front Contact of relay 362, windingof slow-to-release relay 303 to battery. Relay 3% The.

becomes energized and closes a circuit from ground through the leftfront contact of relay 303, winding of slow-to-release relay 304 tobattery. Relay 304 becomes energized and closes a circuit from groundthrough the left outer front contact of relay 304 to the sleeveconductor 18 of connecter Cl for holding the preceding switches in theiroperated positions and to guard the connecter Cl from seizure by otherhunting selector circuits.

As the pulsing contacts 8 and 0 of the dial in subscriber station A areopened, relay 30| will release and close a circuit from ground throughits lower back contact, the left inner front contact of relay 302, theback contact of the vertical off-normal springs V. O. N., winding ofrelay 3|0, winding of vertical magnet 3|2 to battery. This causes relay3|0 and Vertical magnet 3|2 to become energized. Operation of thevertical magnet will cause the switch to take on step in a verticaldirection. As soon as the shaft of connecter CI is moved from the normalposition on the rst vertical step, the V. O. N. springs will operate andtransfer the operating and holding circuit for relay 3|0 under thecontrol of the left front contacts of relay 3|0 and the lower frontcontacts of the V. O. N. springs. When the pulsing contacts 3 and 9 ofthe dial close, relay 30| will reoperate. Relay 302 being slow torelease will remain operated during the pulsing of a digit and therebyholds relays 303 and 304 in their operated position. Relay 3|0 beingslow to release will remain operated also during the pulsing of a digit.As the pulses are sent out from the dial over the subscriber loop, relay30| will operate and release for each pulse of the dial and connecter CIwill take a vertical step for each of the pulses received. As soon asthe first set of. pulses have been transmitted, relay 30| will remain inthe operated position and relay 3|0 will release.

The next set of impulses received from the dial will again cause relay30| to release and to reoperate as previously described. Relay 30| inreleasing will close a circuit from ground through its lower backcontact, the left inner front contact of relay 302, the lower frontcontact of the V. O, N. springs, the left back contact of relay 3|0, theright outer back contact of relay 309, conductor 3|5, the lower innerback contact of relay 301, winding of rotary magnet 3H to battery. Acircuit will be closed also from ground on conductor 3|5, conductor 3|0,winding of relay 303 to battery. Th-e rotary magnet 3I| will functionand cause the shaft of. the connecter Ci to step in a horizontaldirection in response to the number of pulses received from thesubscribers dial. Relay 302 will again remain operated as during thevertical stepping described previously. During the functioning of rotarymagnet 3H, relay 300 will operate in multiple with rotary magnet 3H and,being slow to release, will remain operated during the series of pulsesto close the circuit for testing the called line.

If the called lineV is busy, ground will be connected to the sleeveterminal 342. This will cause relay 309 to operate over a circuitextending from terminal 342, brush 332, conductor 3|1, the right frontcontact of relay 308, the lower back contact of relay 301, winding ofrelay 309 to positivegrounded battery before relay 308 releases. Relay300 having operated will lock as the relay 308 releases over a circuitextending from positive grounded battery, winding of relay 309,

v 309, left outer front contact of relay 304 to ground. Opening of theright outer back contact of relay 300 will open the holding circuit forrelay 300 and for the rotary magnet 3| Closure of the left front contactof relay 309 will close a circuit to busy tone over conductor 3|1. Thisbusy tone will be extended to the calling subscriber in a manner Wellknown to the art.

If the called line is idle, battery will be connected to the sleeveterminal 342. Relay 309 will not operate therefore, and the connecter C|will cut through to the called line upon the release of` relay 308. Whenthe called line is seized, relay 301 will operate over a circuit throughits lower winding upon the release of relay 308. The operating circuitfor relay 301 will extend from battery on terminal 342, through brush332, conductor 3|1, the right outer back contact of relay 308, lowerwinding of relay 301, the right inner back contact or relay 300 toground through the left outer front contact of relay 304. The circuitfor operation of relay 301 is thereby controlled from .ground at relay304 and acts as a guarding potential on the sleeve terminal 342 untilrelay 301 has operated and connected ground through its lower frontcontacts to the sleeve terminal 342. The circuit through the lowerwinding of relay 301 serves only to operate the upper inner frontcontacts of relay 301. This will close a circuit from positive groundedbattery through the winding of rotary magnet 3||, the upper winding ofrelay 301, the upper inner front contacts of relay 301 to ground on theleft inner front contacts of relay 304. This circuit is maintained untilthe release of the connecter CI. The operation of relay 301 also closesa ringing circuit from the ringing machine 3|8, through resistance 319and condenser 320 in parallel with L.

the lower winding of relay 300 to the loop circuit of the calledsubscriber X.

The called subscriber at station X is signaled in any desired manner byuse of the ringing signals. As the ringing continues a ringing tone issent to the calling station A in a manner well lrnown to the art.

The calling subscriber at station A has instructions when calling a freeline, such as line X, to depress the pushbutton 64 to obtain refund ofcoin 28 when he hears ringing tone. When the pushbutton 04 is depressed,coin return lever 30 engages the coin trigger lever 29 and the coin trap33. With the coin return lever 38 in the operated position the coinreturn mechanism used in Fig. 1 assumes the position as shown in Fig.Ll. The end of coin return lever 38 causes the coin trap 33 to pivotabout its fulcrum 05 thereby causing the coin Z8 to be dropped in thedirection indicated` by the arrow 21 and thus returned to the callingsubscriber at station A. As the coin return lever 38 is moved from thenormal to the operated position, the teeth 44 on coin return lever 38engage gear 45 thereby causing gear 45 to turn in a clockwise direction.Turning of gear 45 will cause shaft 41 to turn and thus cause the leverarm 48 to wind up the spring 50 and cause the ratchet 5| to turn in aclockwise direction inside of the ratchet wheel 52. Also, as the coinreturn lever 38 is moved from the normal to the operated position, arm00 attached to coin return lever 38 moves away from surface 33 of T-arrn35 and makes contact with surface 34 of T-arm 35 and thus causes T- arm35 to pivot about fulcrum 30. This permits 'illustration of Fig. 5.

stud 63 on T-arm 35 to move away from contact springs 4| therebypermitting contact springs 1H to break contact and open the subscriberloop circuit.

As the pushbutton 64 is released, the ratchet engages the teeth ofratchet wheel 52 thereby affording a rigid connection between governor5G and the coin return lever 38 by means of the shaft 41. Whenpushbutton 64 is released the spiral spring 50 tends to cause shaft l1and the entire timing mechanism GI to turn in a counterclockwisedirection. The governor 55 is so timed that the control springs 4| willbe held open sufliciently long to permit the release of all selectorsand connecters other than free call connecters, such as Ci of Fig. 3. Inthe case of connecters such as Ci slow-to-release relays 302, 303 and334 have been placed in cascade to slow up the release of the connecteruntil the contact springs 4i become closed after the return of the coin28 by the subscriber at calling station A. As soon as the timingmechanism GI restores, arm 35 recloses contacts 4|, and line relay Sillin connecter C| reoperates to reestablish the holding circuits of slowrelays 352, 333 and 3563. And since this occurs before relay 33t hastime to release, the connection is held. This makes it possible for thecalling party to recover his coin when he calls a free-line.

When the receiver is removed at the called station X, a circuit isclosed to operate relay 305 and cause the ringing signal to cease in amanner well known to the art. Relay 305 will operate to close its upperinner front contacts due to the current flowing through its lowerwinding. This circuit leads from battery, the upper winding of relay335, the upper inner front contacts of relay 3BG, to ground through theleft inner front contacts of relay 354. The operation of relay 303 willconnect the talking leads through to the windings of relay 3135 whichnow supplies talking battery to the called station X. The called stationX and the calling station A are now connected for talking purposes.Under this condition relay 335 will operate. Operation of relay 305 willreverse the direction of the current flow in the metallic loop circuitof substation A described before which is in series with the windings ofrelay 35i. This reversal is accomplished by transferring the negativebattery supply from the lower back Contact to the lower front contact ofrelay 365 and by transferring the ground supply from the upper backcontact to the upper front contact of relay 355. The direction of thecurrent flow is reversed therefore through conductor i3, copper oxiderectifier I5, coin magnet ifi and conductor l2. The copper oxiderectifier i5 will permit current to pass through this circuit under thiscondition and the coin magnet i4 will operate. Operation of the coinmagnet Ut will operate the coin trap 33 as shown in the detail Operationof the coin trap 33 will reset the coin trigger lever 29, the cointrigger 32 and the contact springs 35. With the functioning of thecontact springs 30, the front contacts will open and the back contactswill close. Opening of the front contacts will open the circuit throughthe copper oxide rectifier l5 and the coin magnet i4 thus removing thebridge from the line and permitting coin magnet M to release. Closure ofthe back contacts of contact 3U will close the talking circuit throughto the transmitter l5. The calling party may then talk to the calledsubscriber in the usual manner.

If it is desired to abandon the call at the substation A because theline of the called subscriber X is busy or because the called subscriberX does not answer, the receiver at substation A is replaced on theswitchhook I9 and the subscriber at station A depresses pushbutton 64.When the push button 64 is depressed the coin return mechanism GIfunctions and the coin 28 is returned to the subscriber as describedheretofore.

After conversation is completed and the subscriber at called station Xdisconnects, relay 335 will release and when the calling station Adisconnects relays 30|, 332, 333 and 334 will release which in turnallow relay 331 to release. With the connecter Cl in this condition acircuit is closed from positive grounded battery, winding of releasemagnet 3|3, upper front contacts of the V. O. N. springs, upper backcontact of relay 391, right back contact of relay 304, left back contactof relay 332 to ground on the lower back contact of relay 30| Therelease magnet 3|3 being energized will release connecter Cl which willrestore the connecter shaft to normal. When the shaft returns to normalthe V. O. N. springs are operated thereby opening the circuit to therelease magnet 3|3 and allowing it to release. When the called station Xor the calling station A are disconnected, supervisory signals are givenover conductors 3|5 and 3|6 to common alarm equipment not shown. Theremoval of ground from conductor 78 also causes the release of finder LFand selectors Sl and S2.

Assuming that the subscriber at station A desires to make a call to lineY for which payment is required, he removes the receiver 23 from theswitchhook i9. The line finder LF and selectors Si and S2 will function`as described heretofore when the subscriber at station A makes a freecall, except that, because of grouping arrangements, the selector S2will seize a connecter such as C2 by way of conductors i9, 83 and 8|.When the connecter C2 is seized the subscriber loop is closed to batteryand ground through the windings of relay 328. Relay 328 will operate andclose a circuit from ground through its lower front contact, winding ofslow-to-release relay 32i to battery, thereby causing relay 32| tooperate. As the digits are dialed at substation A, relay 323 willrelease on the rst pulse of the dial but relay 32| will remain operated.A circuit will be closed thereby for operating the connecter C2 in thesame manner as outlined heretofore for connecter CI, relay 32| remainingoperated during the pulsing for any digit.

The called subscriber Y is signaled in a manner well known to the art.If the subscriber' at calling station A depresses push button 53 at anytime before the called station Y answers, the subscriber loop will beheld open long enough by the governor assembly GI for the relays 323 and32| to release, thereby closing the circuit to the release magnet 322and allowing the connecter C2 to restore to normal. When the calledstation Y answers a reversal of battery and ground over the callingsubscriber loop at station A is created in connecter C2 in a manner wellknown to the art. The coin collect mechanism at station A will functionas outlined heretofore when a battery reversal was made when usingconnecter Cl and the deposited coin will enter the Vcoin hopper in thedirection indicated by arrow 2t?.

Assuming that a call originating at station A has been routed byselector S2 to an intercepting operators position 0 by way of conductors82, 83 and 84, the transmitter circuit at station A will extend fromconductor I, front contacts of springs 3G, conductor I l, pulsingcontacts 8 and 9 of the dial, copper oxide rectier Il, conductor 25,transmitter l5 to conductor I8 and the re- 5 ceiving circuit Will extendfrom conductor IFJ through condenser 22, right Winding of induction coil2Q, right contacts of svvitchhook I9, receiver 23, conductor Eil,contacts 5 and 6 of the dial to conductor i8. This circuit arrangementallows the calling subscriber at station A to converse with theintercepting operator at position O Without disposing of the coin. It nocharge is to be made the coin may be refunded at the calling station Ain the manner outlined heretofore. If a charge is to be made theoperator at position 0 completes the call in a manner Well known to theart. When the called station answers a battery reversal is obtainedwhich causes coin mag-v net I4 to function and collect the coin 23 inthe Same manner as outlined heretofore.

Let us assume that the calling substation A desires to obtain aconnection to the zero operator. In this event no coin is required. Thereceiver 23 at substation A is removed from the 25 switchhook I9, andthe dial at substation A is operated and released in accordance with thecode number of the Zero operator, which is usually 0. As the dial ismoved from the normal position, springs 5 and l of the dial are closedand springs 5 and E are opened. Spring 2 of the dial will not makecontact with spring 3 and spring 4i Will not break contact from spring 2until the dial has been fully operated to the 0 position when saidsprings will operate and remain locked in their operated positions thusclosing the pulsing circuit and opening the transmitter circuit toprevent pulsing through the transmitter Iii until the dial has restoredto normal. Opening of contact springs 2 and i will open the circuitthrough the transmitter i6. Closure of contact springs 2 and 3 willcomplete a metallic pulsing circuit through conductor 2l, the leftwinding of the induction coil ES, the left contacts of svvitchhook i8,conductor i3, contacts E and 'i and pulsing contacts 8 and Q andcontacts 2 and S of the dial, the back contact of contact springs 3d, toconductor I0. The selector SI will accordingly be set in accordance withits primary movement upon the proper trunk level which We will assume tobe the 10th or 0 trunk level of the switch. The selector SI willfunction in the usual manner and extend the connection to the zerooperator displaying a signal at her position as an indication that acall is in Waiting. When the call is ansvvered by the zero operatorthere is no current reversal in the calling line loop, thus preventingthe operation of the coin magnet Ml. The zero operator will complete thecall in a manner Well known to the art.

G0 Referring to Fig. 2, substation B, in addition to the usual receiverand transmitter, comprises a special coin collect mechanism consistingof contact springs l3ll, a coin chute IM, a coin trigger I32, a cointrigger lever i253, a coin trap ISE, a non-polarized coin magnet IM, acopper oxide rectier M5. substation B has also a special governor andcoin return mechanism G2 the same as that described in Fig. l. Inaddition to this apparatus substation B is equipped With a special dialin order to prevent the calling substation B from dialing any digitother than 0 Without depositing a coin in the coin mechanism. This dialis similar to the dial shown diagrammatically in Fig. 6 and used atstation A. The outward ap- 75 pearance of the dial is similar Ato thatof any standard dial. It has a finger Wheel, a number plate and a fingerstop identical with the parts shown in Fig. 6. The interior of the dialhas a special construction and consists of contact springs 32 to lQ,inclusive. The cam Which rotates in unison with the finger wheel, thelever arm which has a roller conveniently attached at one end, thecollar having an inner surface and an outer surface, the pulse pawl, thepulse pawl spring and the pulse Wheel are the same and function the sameas those described in Fig. 6. The lever arm, which has the rollerattached at one end, joins spring m3 so that any movement of the leverarm is transmitted to spring HB3.

When the linger wheel is moved from its normal position the cam moves ina clockwise direction and permits springs H05 and lllii to make contactand springs and lill to break contact. As

soon as the finger Wheel is moved in a clockwise direction, the rollerand the lever arm will function as described for Fig. 6, in such amanner as to keep springs M32 and Ide from breaking contact and springsIilS and lli from making Contact until the digit 0 has been completelydialed When the roller and the lever arm Will drop from the surface ofthe collar and permit spring los to make contact With spring IM andspring W3 to break contact with spring m2. When the iinger Wheel isreleased the roller on the lever arm Will contact With the outer surfaceof the c-ollar in such a manner as to hold springs lo? and Ill?, openand springs H33 and iii@ closed until the finger Wheel has restored toits normal position Where the lever arm again assumes its normalposition as shown in Fig. 6. The pulsing springs w8 and it@ are operatedin the usual manner by pulse paWl.

Referring to Fig. 2, let us assume that a party at the callingsubstation B removes the receiver E23 from the switchhook IE@ to make afree call. Although payment is not required, he must deposit a cointemporarily to enable him to make the call. When the receiver I23 isremoved from the switchhook I i9 a metallic loop circuit will be closedthrough substation B from terminal E98, over line E59, conductor Il, theback contacts of contact springs i3d, springs H32 and liii of the dial,conductor l25, transmitter lili, conductor H8, the left contacts ofSWitchhook H9, the left Winding of induction coil H29, conductor l2l,line l to terminal ISI, A receiving circuit will be 'closed fromconductor IIS, through condenser i522, the right Winding of inductioncoil me, the right contacts of switchhook I i9, receiver l23, conductorIM, contact springs H35 and ld of the dial to conductor H8.

The brushes of the line finder LF will connect with the terminals I9@and EQI and extend the metallic loop circuit of substation B describedabove through to a selector Si. The selector Si will function to senddial tone to the calling substation B and to place negative battery onconductor l2l and ground on conductor lio of the metallic loop circuitof substation B. Under these circumstances dial tone Will be heard inthe receiver IZB of substation B. If no coin has been deposited at thecalling substation B, the contact springs I3@ of the coin mechanism ofsubstation B will not operate and since contact springs IS and Iiii ofthe dial will not make contact when any digit other than 0 is dialed thepulsing cir-cuit will not be closed through. This prevents dialing fromthe calling substation B until a coin is deposited in coin chute i3! ofthe coin mechanism. If on or before receiving the dial tone, the callingparty deposits a coin |20 in the coin chute |3|, the coin |28 Will passthrough the coin chute |3| to the coin trap |33 thereby operating thecoin trigger |32 which in turn will allow the coin trigger lever |20 tooperate. Operation of the coin trigger lever |29 will cause the contactsprings |30 to function closing the front contacts and opening the backcontacts of said contact springs |30. Opening of the back contact willopen the transmitter circuit. Closure of the front contacts of springs|30 will close a loop circuit through conductor the pulsing springs |03and |09 of the dial, conductor H3, winding of coin magnet H43, copperoxide rectifier H5, conductor ||2 to conductor I 8. The copper oxiderectifier H is a unipolarity device which will not permit current topass through in the direction opposite to that indicated by the symbolicarrowhead. Therefore, coin magnet ||4i will not operate. A parallel pathleads through the retier III, which serves the same function as didrectifier il in Fig. l. Closure of the front contacts will complete thepulsing circuit from conduetor IIil, the front contacts of contactsprings |30, conductor pulsing springs |03 and |09 of the dial, offnormal springs |05 and |071 of the dial, conductor IIIS, the leftcontacts of switchhook 9, the left winding of induction coil I 20 toconductor |2I. Contact springs |02, |03 and |04?, of the dial will notoperate when a digit other than 0 is dialed. As the dialis moved offnormal, contact springs |05 and I 03 of the dial break contact to openthe receiver circuit and contact springs i053 and |01? make contact toplace a 'r short circuit around the coin magnet IM and at the same timeto close the pulsing circuit. The dial is then operated and released inthe usual manner causing the selector SI and the selector S2 tofunction.

Assume that selector S2 seizes a connecter such as C| and closes thesubscriber loop thereto, the call will be completed in the manneroutlined herein for substation A. When ringing tone is heard thesubscriber at station B will obtain a refund of the deposited coin |28by operation of coin return mechanism G2. rIhe talking circuit will beestablished as outlined heretofore for station A.

Assuming next that the called station B desires to make a call for whichpayment is required, the circuit at station B, the line finder LF, theselectors SI and S2 and the connecter C2 will function as outlinedherein for station A when making a similar call. When the called stationY answers, the current ow through the subscriber loop at station B willbe reversed in the manner described heretofore in the operation ofstation A, thereby reversing the current flow through conductor ||3,coin magnet IM, copper oxide rectifier H5, and conductor ||2. The copperoxide rectifier I5 will permit current to pass through this circuitunder this condition and the coin magnet ||4 will operate. Operation ofthe coin magnet II 4 will operate the coin trap I 33. Operation of thecoin trap |33 will reset the coin trigger lever |29, the coin trigger|32 and the contact springs |30 and will collect the coin |28 in themanner outlined for station A. With the functioning of the contactsprings |30, the front contacts Will open and the back contacts willclose. Opening of the front contacts will open the circuit through thecopper oxide rectifier ||5 and the coin magnet ||4 thus removing thebridge from the line and permitting coin magnet ||4 to release. Closureof the back contacts of contact |30 will close 'the talkingl circuitthrough to the transmitter I6. The calling party may then talk to thecalled subscriber in the usual manner.

If it is desired to abandon the call at the substation B because theline of the called subscriber Y is busy or because the called subscriberY does not answer, the receiver at substation B is replaced on theswitchhook IIS and the subscriber at station B depresses pushbutton ofthe coin return mechanism G2 to obtain refund of the coin.

On a call to the intercepting operators position 0, the circuit atstation B will function in the manner outlined heretofore when making af free call but the calling subscriber at station B must refund his coinbefore he can talk to the intercepting operator at operators position 0.

Let us assume that the calling substation B desires to obtain aconnection to the zero operator. In this event the receiver |23 atsubstation B is removed from the switchhook H0 and the dial atsubstation B is operated and released in accordance With the code numberof the Zero operator, which is usually 0. As the dial is moved from thenormal position, springs |00 and I 0l of the dial are closed and springs|05 and |06 are opened. Spring |03 of the dial will not make contactwith spring |04 thus keeping the pulsing circuit open and spring |03will not break contact from spring |02 thus keeping the transmittercircuit closed until the dial has been fully operated to the 0 positionwhen said springs will operate and remain locked in their operatedpositions thus closing the pulsing oircuit and opening the transmittercircuit to prevent pulsing through the transmitter Il@ until the dialhas restored to normal. Opening of contact springs |02 and |03 will openthe circuit through the transmitter H6. Closure of contact springs |03and |04 will complete a metallic pulsing circuit through conductor |25,the left winding of the induction coil |20, the left contact ofswitchhook I I4, conductor I I0, olf-normal contact springs |00 andIOTI, pulsing contact springs |08 and |09 of the dial, conductor IH,contact springs |03 and |04, back contacts of springs |30, conductorIIB.

The selector SI will accordingly be set upon the proper trunk levelwhich we will assume to be the 10th or 0 trunk level of the switch. Theselector SI will function in the usual manner and extend the connectionto the zero operator displaying a signal at her position as anindication that a call is in waiting. When the call is answered by thezero operator there is no current reversal in the calling line loop,thus preventing the operation of the coin magnet IM. The zero operatorwill complete the call in a manner well known to the art.

What is claimed is:

1. In a telephone system, a calling line having a coin-controlledstation thereon, a rst called line and means for establishing aconnection thereto from said calling line, a second called line andmeans for establishing a connection thereto from said calling line,refunding means for refunding a coin deposited at said station withoutreleasing a connection established to said rst called line, and meansfor releasing a connection established to said second called line inresponse to the operation of said refunding means.

2. In a telephone system, a coin-controlled station, means for settingup a connection from said station to either of two differentdestinations, a refund device operable to refund a coin deposited atsaid station without releasing one of said connections, and meansresponsive to the operation of said device for releasing the other ofsaid connections.

3.`In a telephone system, a coin-controlled station, means forestablishing a connection from said station to either of twodestinations, a refund device operable to refund a coin deposited atsaid station without releasing one of said connections, means responsiveto the operation of said device for releasing the other of saidconnections, and means controlled from said station for releasing eitherof said connections.

4. In a telephone system, a coin-controlled station having an impulsedial thereat, two different called stations, automatic switchesresponsive to said dial for establishing a connection from thecoin-controlled station to either of said called stations, a refund keyat the coin station for refunding a deposited coin, means for holdingthe connection established to one of said called stations when therefund key is operated, and means responsive to the refund key forreleasing the connection established to the other of said calledstations.

5. In a telephone system, a coin line having a coin-controlled station,called lines some of which may be called free and some of which requirea charge, means controlled by the deposit of a coin for enabling theparty at said station to establish a connection either to one of saidfree lines or to one of said charge lines, means to collect the coinautomatically when the called party answers, means for refunding thedeposited coin before the called party answers, means for holding theconnection to one of said free lines when the coin is refunded, andrelease means for releasing the connection to one of said charge lines.in response to the refunding of the coin.

6. In a telephone system, a calling line having a coin station thereon,called lines some of which may be called free and some of which requirea charge, means controlled by the deposit of a coin for enabling thecalling party to establish a connection to a free line or to one of saidcharge lines, means to collect the coin automatically on the response ofthe called party, means for refunding the coin and for opening theestablished connection for an interval before the called party answers,means for holding the connection to a free line to prevent releaseduring said open interval, and release means for releasing theconnection to a charge line in response to the opening of saidconnection.

7. In a telephone system, a calling line having a coin-controlledsubstation thereon, switchhook contacts at said substation for openingand closing the line, a called line, automatic switches for establishinga connection between the calling and called lines, a refund device atsaid substation for refunding a deposited coin and for opening thecircuit of the calling line, release means controlled over said callingline for eifecting the release of said automatic switches, and meansassociated with said release means for distinguishing between an openingof the calling line caused by said refund device and an opening causedby said switchhook contacts.

8. In a telephone system, a calling line having a coin station thereon,a called line, automatic switches, a dial at the calling station foroperating said switches to establish a connection to said called line,means at the calling station for receiving a deposited coin, refundmeans at the calling station operable to refund the deposited coin andto open temporarily the established connection, and means for holdingthe established connection for conversation after the coin has beenrefunded.

9. In a telephone system, a calling line having a coin station thereon,a called line, automatic switches, a dial at the calling station foroperating said switches to establish a connection to the called line,means at the calling station to receive a deposited coin, m'eans at thecalling station for refunding a deposited coin and for opening theconnection for an interval, means for holding said connection duringsaid interval, and means controlled from the calling station forreleasing said connection.

l0. In a telephone system, a calling line having a coin-controlledsubstation thereon, a called line, automatic switches, means controlledby the deposit of a coin at said coin station for enabling the callingparty to operate said switches to establish a connection to the calledline, means for collecting the deposited coin in response to the answerof the called party, means at the calling station for refunding adeposited coin before the called party answers, means for holding theestablished connection after the coin has been refunded, and means forreleasing the established connection.

1l. In a telephone system, a calling line having a coin-controlledstation thereon, a called line of one class, a called line of a secondclass, automatic switches, means for establishing a connection from thecoin line over Said automatic switches to the first mentioned calledline, means for establishing a connection from the calling line oversaid automatic switches to the second mentioned called line, said secondestablished connection including a particular one of said switches,means for refunding a deposited coin at the calling station, and meansin said particular switch for holding the established connection duringthe refunding of the deposited coin.

12. In a telephone system, a calling line having a coin-controlledstation thereon, a called line, means for establishing a connectionbetween said lines, a refund key at the calling station for restoringthe deposited coin and for opening the connection, a timing devicecontrolled by said key for reclosing a connection at the end of aninterval, and means for holding said connection during said interval.

13. In a telephone system, a calling coin line, a called subscribersline, means on the calling line for receiving a deposited coin, contactsoperated by the deposited coin, means for establishing a connectionbetween said lines, a refund key for refunding the deposited coin, forrestoring said coin operated contacts, and for opening the line, atiming device set by said key and serving to reclose the line after ameasured interval, means associated with the established connection forholding the same against release while said line is open, and othermeans for opening said line to cause the release of said connection.

SAMUEL B. WILLIAMS.

